This invention relates generally to systems and apparatuses for preventing over temperature conditions in a non-fire zone of an aircraft engine, and more specifically to an over temperature fuse in a signal tube.
In the art, the full authority digital electronics control (FADEC) for a gas turbine engine utilizes a pressure signal from the combustor for control of the engine. Because a broken signal tube could allow hot air to enter the fan compartment, a non-fire zone, the FADEC shuts down the engine in a broken signal tube condition. The broken signal tube could be due to, for example, improper maintenance, tube fatigue, or foreign object damage from the aircraft to the engine.
For weight considerations, the signal tube is usually not insulated in the non-fire zone. Additionally, many engine programs use composites in the fan and nacelle compartments where leaking high temperature air can do damage. Temperature sensors and shut-off valves could be used to minimize the risk of leakage, but reliability, cost, and weight are negative factors.
Accordingly, it would be desirable to have a low cost, low weight, detection system that seals off flow of high temperature air in the non-fire zone.